Red Hat ENTERPRISE LINUX 5 - LOGICAL VOLUME MANAGER ADMINISTRATION Przewodnik Instalacji Pobierz pdf (Strona 87)

The volume group metadata contains:

• Information about how and when it was created

• Information about the volume group:

The volume group information contains:

• Name and unique id

• A version number which is incremented whenever the metadata gets updated

• Any properties: Read/Write? Resizeable?

• Any administrative limit on the number of physical volumes and logical volumes it may con-

tain

• The extent size (in units of sectors which are defined as 512 bytes)

• An unordered list of physical volumes making up the volume group, each with:

• Its UUID, used to determine the block device containing it

• Any properties, such as whether the physical volume is allocatable

• The offset to the start of the first extent within the physical volume (in sectors)

• The number of extents

• An unordered list of logical volumes. each consisting of

• An ordered list of logical volume segments. For each segment the metadata includes a

mapping applied to an ordered list of physical volume segments or logical volume seg-

ments

3. Sample Metadata

The following shows an example of LVM volume group metadata for a volume group called

myvg.

# Generated by LVM2: Tue Jan 30 16:28:15 2007

contents = "Text Format Volume Group"

version = 1

description = "Created *before* executing 'lvextend -L+5G /dev/myvg/mylv /dev/sdc'"

creation_host = "tng3-1" # Linux tng3-1 2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:21 EST 2007 i686

creation_time = 1170196095 # Tue Jan 30 16:28:15 2007

myvg {

id = "0zd3UT-wbYT-lDHq-lMPs-EjoE-0o18-wL28X4"

seqno = 3

status = ["RESIZEABLE", "READ", "WRITE"]

3. Sample Metadata

1 2 ... 82 83 84 85 86 87 88 89 90 91 92

Brak uwag

Red Hat ENTERPRISE LINUX 5 - LOGICAL VOLUME MANAGER ADMINISTRATION Przewodnik Instalacji Strona 87